The present invention relates to solid 2-octynyl adenosine with novel properties which does not decompose at a high temperature or at a high temperature and under a high humidity and thus which is stabilized with respect to temperature or temperature and humidity.
2-Octynyl adenosine is a compound wherein an octynyl group is introduced into the 2-position of adenosine through a carbon-carbon bond, and has an antihypertensive activity. The development of 2-octynyl adenosine as medicines is anticipated. (See Nucleic Acids Research Symposium Series No.12, pp.5-8 (1983), Chem. Pharm. Bull., 33, pp.1766-1769 (1985), Nucleic Acids Research Symposium Series No.16, pp.97-100 (1985), Nucleosides & Nucleotides, 6 (1&2), pp.85-94 (1987), Japanese Patent Laid-Open Publication No. 99395/1987, Japanese Patent Laid-Open Publication No. 99330/1987, and U.S. Pat. No. 4,956,345.)
Heretofore, 2-octynyl adenosine has been generally produced in the final step in the form of a monohydrate crystal by gradually crystallizing from a methanol/water solvent mixture (ordinarily methanol containing 10 to 50% water) or in amorphous form by rapidly depositing from a methanol/water solvent mixture. However, it is well known that the water content of the thus obtained compound is ordinarily 4.6% or higher so that the compound is unstable with respect to temperature and humidity. For example, according to the results of a severe test for evaluation of its long-term storage stability (stored for 3 months at 40.degree. C. under a relative humidity of 75%), the percentage of the remaining crystalline 2-octynyl adenosine monohydrate or amorphous 2-octynyl adenosine is about 70%. (See WO90/15812.) Therefore, it is impossible to enjoy such a "scale" merit that 2-octynyl adenosine produced on a large scale is stored until it is needed, whereby 2-octynyl adenosine must be produced on a small scale when needed. When the production of a large amount of 2-octynyl adenosine is required, a special apparatus capable of controlling temperature and/or humidity has to be employed in order to store the 2-octynyl adenosine.
Accordingly, if 2-octynyl adenosine stabilized with respect to temperature and/or humidity is obtained, great industrial benefits can be achieved.
It is therefore an object of the present invention to provide 2-octynyl adenosine with novel properties which is stabilized with respect to either temperature or humidity, preferably with respect to both factors.